Magnetic separator



Jan. 9, 1962 H. SPODIG MAGNETIC SEPARATOR Filed Sept. 29, 1958 INVENTOR. d/017:4 .sfaay Sfr/e firm United States Patent MAGNETIC SEPARATOR Heinrich Spodig, Netteberge 84, Bork, Westphalia,

1 Germany Filed Sept. 29, 1958, Ser. No. 763,894 Claims priority, application Germany Oct. 6, 1949 1 Claim. (Cl. 209--223) of my application Serial, No. 186,728 filed September 26, r

1950, now Patent No. 2,707,557.

In such a part-magnetic separator a non-magnetic drum is rotatable about a magnet system arranged within the drum in such a mannerthat the drum is thereby divided into a magnetically effective peripheral portion and a complementary magnetically ineffective portion.

The invention aims to improve, for example, the efficiency of those separators in which the magnetic system consists of an even number of rod-shaped permanent magnets and a ferro-magnetic or magnetizable plate connecting the magnets and having the shape of a sector covering part'of the inner surface of the drum. The permanent magnets are connected with the sector plate in such a manner that the latter shows the magnetic zero potential whereas the magnetic circuit is closed by the drum shell or by the'materials to be separated. Ferro+ magnetic or magnetizable bodies which are covered by the drum shell and ferro-magnetic' particles adhering thereto are separated on'that'side of the separator which is opposite to the magnetic rods within the effective range of the sector plate.

However, the effectiveness of separation of such prior separators is not satisfactory, particularly so where the particles to be separated are small. The reason is that the sector-shaped plate has a magnetic zero potential only in therange where the magnets having uneven polarities are located directly next to one another, whereas the opposite zones of the plate show magnetic dispersion which makes the non-magnetic range of the plate comparatively small, leaving the non-magnetic and the magnetic zones v of the separator insufiiciently demarcated against each other. i

This invention also aims to improve art-magnetic separators of a kind exemplified'in the U. S. patent to Jobke No. 1,714,171. p

It is an object of the present invention to provide a magnetic separator of improved efliciency, which is simple in construction, and in which the magnet system within the drum is so arranged that the drum periphery will be sharply and effectively subdivided into the respective magnetic and non-magnetic. portions, that is with magnetic dispersion effects in the non-magnetic or neutral portion of the drum eliminated.

To attain this object, the invention provides in the magnet system of the separator a ferro-magnetic or magnetizable member as distinct from permanent magnetic steel, which may selectively serve as a magnetic short circuit body or as a conductor of one or more polarities, and by means of the drum surface which has a direct relationship to the magnet poles.

In the improved magnet system of this invention,

there is provided a supporting plate or carrier plate member of ferro-magnetic material as distinct from permanent magnetic steel, extending longitudinally within the drum substantially from end to end thereof. This ICC plate member or means is suitably supported within the revolving drum with its longitudinal edges adjacent to the inner surface of the drum. A system of magnets or magnet rods is mounted upon one side of this plate extending towards the respective surrounding portion of the drum periphery, the plate thus in effect dividing the drumperiphery into a magnetically effective portion facing the magnets and a complementary non-magnetic neutral portion facing the opposite side of the plate.

Preferably, the arrangement of the magnet rod according to the invention is such that the edge portions of the plate assume equalpolarities with the result that magnetic dispersion in the non-magnetic or neutral portion of the drum is avoided;

In one embodiment, such an arrangement with equal polarities at the plate edges is attained by'an arrangement in which permanent magnets or magnet rods are disposed in parallel rows or planes transversal of the drum axis, with the polarities at their outer ends alternating between N and S or positive and negative polarities.

Preferably, each row has an uneven number of such magnets so that the outer ends of the magnets at the ends of each row will have equal polarity.

In another embodiment, there are parallel transverse rows of permanent magnets all having outer ends of the same polarity, with conductors or conductor tongues of ferro-magnetic material fixed on the ferro-magnetic plate in alternation with the permanent magnets of each row, so that the conductors through the plate assume equal polarity although opposite to that of the outer ends of the permanent magnets of the system.

"Features lie in various configurations of the ferro -magnetic plate, as well as in various arrangements of the magnet members on that plate. I

The novel features which are considered as characteristie for the invention are set forth in particular in the appended claims. The invention itself, however, both as to-its construction and its method of operation, togetherwith additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, inwhich:

FIG. 1 is a longitudinal sectional view of the separator illustrating one embodiment of the magnet system in the drum, with the ferro-magnetic supporting plate extending diametrically in the drum;

FIG. 2 is a transverse sectional view of the separator taken on line 2-2 of FIG. 1;

FIG. 3 is a longitudinal sectional view of the separator illustrating another embodiment of the magnet system in the drum, with the ferro-magnetic supportingplate partially surrounding the axis of the drum;

FIG. 4 is a cross-sectional view of the separator taken on line 4 -4 of FIG. 3;

FIG; 5 is a cross-sectional view of a separator similar to the one shown in FIGS. 3 and 4,with a magnet arrangement featuring a combination of permanent 'magnets with term-magnetic elements on the ferro-magnetic supporting plate. v

In each of the embodiments the magnet system comprises a ferro-magnetic supporting plate carrying a system of magnets upon one side thereof and magnetically connected therewith. This plate may carry the most suitable number of magnets in various arrangements, dependent upon the size of the drum, its magnetic range, and its force of attraction.

Referring to the drawings, the separator comprises a drum 1 of non-magnetic material which carries'upon its outer surface magnetizable rods 2 extending parallel to the drum axis and equidistantly spaced from one another along the periphery of the drum, for the purpose of providing a system of magnetic flux lines such as set forth in my U.S. Patent No. 2,707,557, and indicated in dotted lines.

The magnet system in the embodiment of FIGS. 1 and 2 comprises a supporting plate 9 mounted on the axle 3 and extending substantially diametrically, as well as substantially from end to end of the drum. Upon one side this supporting plate carries magnetically connected thereto a system of permanent magnets 5, which, for example, comprises two longitudinal rows of permanent magnets 5 extending from the supporting plate to the respective surrounding portion of the drum. periphery. The outer ends of magnets of the two rows which may be symmetrically arranged are of opposite polarities so that in this instance the edge portions E and E of the plate are also of opposite polarities with respect to each other. i

In effect, the edges E and E of the plate thus divide the drum periphery into a magnetically efiective peripheral portion P and a non-magnetic complementary peripheral portion P Although the edge portions of the plate have opposite polarities, it is because of the large distance between these edges that a magnetic flow through the drum space 6 corresponding to the peripheral drum portion P does not result and actually takes place only through the magnets 5, so that practically a zero or neutral zone P is obtained free from magnetic dispersion.

The magnet arrangement inside the drum according to the embodiment in FIGS. 3 and 4 comprises a ferromagnetic supporting plate 9a also mounted on the axle 3 of the drum. This plate is of U-shaped cross-sectional configuration partially surrounding the axle 3 with slightly outwardly flaring longitudinal edge portions E and E located adjacent to the inner surface of the drum. More precisely, the profile of this plate is in the form of an open polygon the sides of which may provide the seat or connection for the magnets to be carried by this plate. That is to say, a system of permanent magnets 5a is provided rigidly upon the outer face of this specially shaped sup porting plate. The arrangement of these magnets may be in trans-verse rows or planes which are parallel to one another. Preferably, each row has an uneven number of such magnets, for example five, so arranged with alternating polarities that the opposite end magnets of each transverse row have at their outer poles the same polarity, whereby there are imparted to the edge portions E and E of the plate polarities whichare equal relative to each Otheralthough opposite to the polarity of the outer ends of the end magnets of each transverse row.

Here, the edges E and E of the plate divide the drum into the magnetically effective peripheral portion P and the complementary non-magnetic or neutral portion P In this instance, magnetic dispersion in the neutral portion P is avoided because of the mutually repelling equal polarities at the edges E and E of the plate.

The magnet arrangement inside the drum according to the embodiment in FIGURE 5 resembles that of FIG- URES 3 and 4 and a cross-sectional view is sutficient since in longitudinal section the appearance would be the same as that of FIGURE 3 of the preceding embodiment. In FIGURE 5 there is a ferro-magnetic supporting plate 9b similar to the plate 9a in FIGURE 4, but the magnet system itself connected to this plate comprises parallel transverse rows each representing a combination of permanent and ferro-magnetic magnet rods. The permanent magnet rods 5b are of equal polarity at their outer ends, and conductors or conductor tongues 8a of ferro-magnetic material alternate with the permanent magnets in each transverse row. With both the permanent magnets 5b and the conductors 8a connected to the term-magnetic plate, it will be seen that the conductors 8a assume the polarity opposite to the polarity at the outer ends of the permanent magnets so that together they will constitute a magnet system to effect the separation, yet at a substantial saving in construction cost because of the saving in permanent magnetic steel.

Again, the edges E and E of the plate 9b in FIG- URE 5 divide the drum periphery into a magnetically effective portion P and a complementary non-magnetic neutral portion P with the feature that due to the equal polarities at the plate edges, the portion P is kept free from magnetic flux dispersion.

The term-magnetic supporting plate may consist of a single plate element extending along the length of the drum, or for reasons of convenience in assembly, it may be composed of sections.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of magnetic separators differing from the types described above.

It will be understood that as tar as the invention is concerned the magnets on the supporting plate need not be limited to the exact arrangement shown. For example, with embodiment of FIG. 3, the permanent magnets have been shown as being ofiset from one another in an axial direction although in a preferred form they may be aligned in rows transversely of the longitudinal drum axis. The same consideration applies to the embodiments of FIGS. 2 and 5.

While the invention has been illustrated and described as embodied in a magnet system within the separator drum featuring a 'ferro-magnetic supporting plate for the magnets, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any wayfrom the spirit of the present invention.

Without further analysis, the foregoing. will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are in.- tended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as. new and desired to be secured by Letters Patent is: I I l A part-magnetic separator. comprising, in. combination, a non-magnetic drum; stationary carrier plate means of term-magnetic material extending v longitudinally in said drum and having longitudinal edge portions adjacentthe inner surface of the drum; a group of permanentmagnet units carried by said; plate means axially. spaced: from one another so that the magnetic circuit is closedthrough said plate means, each unit having an uneven number of permanent magnet rods mounted on one side of said plate means to extend toward said drum in a plane transversal of the axis of said drum and so arranged that the polarities of the outer ends of the rods are of equal sign; and an even number of complementary magnetic rods of ferro-magnetic material mounted on said plate means in alternation with said permanent magnet rods and assuming at their outer ends the polarity of the inner ends of said permanent magnet rods so that the outer ends of the magnetic rods closest to said longitudinal edge'portions have the same polarity, said plate means thus dividing the drum into a magnetically effective peripheral portion and a complementary magnetically ineifective portion, with said longitudinal edge portions of the plate means presenting polarities of'equal sign.

(References. on following. page).

References Cited in the file of this patent UNITED STATES PATENTS Feeley Aug. 15, 1911 Jobke May 21, 1929 5 Stefiensen May 30, 1939 Stearns Apr. 14, 1953 6 FOREIGN PATENTS Great Britain Nov. 23, 1922 Great Britain Jan. 3, 1924 Germany Nov. 27, 1931 Great Britain Nov. 11, 1935 Great Britain Feb. 25, 1937 Great Britain June 23, 1939 

